With the rapid development of electric vehicles, lithium batteries have been more widely used. Lithium battery materials develop rapidly, and longer driving mileage of electric vehicles requires a higher energy density of the lithium-ion battery. Because of high specific capacity, good performance and low price, ternary material has been developed rapidly. Among them, high-nickel ternary material is deemed as one of the most promising cathode material for lithium ion battery due to a higher specific capacity.
During the practical application process of high nickel materials, there are battery safety problems, while there are problems of large magnification and poor cyclic electrochemical performance. In order to improve the lithium battery capacity, while taking into account the battery safety issues, high nickel materials and other materials (such as LiMn2O4, LiCoO2, Li (Ni1/3Co1/3Mn1/3) O2, etc.) are generally mixed, or the electrochemical performance is improved by coating, so as to achieve the purpose of improving the overall efficiency.
CN103715413A provides a process for preparing monocrystalline ternary cathode material coated with ZnO, comprising weighing lithium carbonate, ternary precursor [Ni0.5Co0.2Mn0.3] and magnesium oxide, mixing and calcining to obtain a Sample one, then weighing lithium carbonate, cobalt oxide, magnesium oxide, mixing and calcining to obtain a Sample two, weighing the Sample one, Sample two and titanium dioxide, mixing, calcining to obtain the final mixture. The process comprises coating the ternary material by a solid phase method, mixing with lithium cobaltate and calcining for use. The resultant material has no uniform coating, more agglomeration of particles, complex operation process and high cost.
CN103618064A provides a process for preparing alumina-compounded nickel-cobalt-lithium manganate ternary material, comprising using the soluble salts of Ni, Co and Mn and ammonia as the complexing agent, sodium hydroxide, sodium carbonate, ammonium bicarbonate as the precipitant, co-precipitating to synthesize a composite ternary precursor, then adding dropwise the soluble salt solution of aluminium into the synthesized precursor solution, filtering, drying, dosing and calcining to form a ternary cathode material. The process provides a process of coating low-nickel ternary material (LiNi1/3Co1/3Mn1/3O2) with alumina. Although the cycle performance is improved, the electrochemical capacity is lower.
CN103022471A provides a method for improving the electrochemical performance of a high nickel ternary cathode material, comprising first preparing the soluble Co salt into a solution and then dispersing the high nickel ternary cathode material into the soluble cobalt salt solution and stirring, adding dropwise the soluble lithium salt, spray drying the resulting mixture liquid, and calcining to obtain a coated ternary cathode material. The process comprises re-coating the surface of the prepared ternary cathode material, drying by spraying, and then re-calcining, and the cost is higher.
It can be seen that there is a problem that the high-nickel-lithium battery material is insufficient in the prior art, and there are problems such as battery safety, electrochemical cycles, magnification and higher cost.